Continuously-acting centrifuge



Dec. 19, 1967 N. KHIBNIK 3,358,841

CONTINUOUSLY-ACTING CENTRIFUGE Filed Oct. 15, 1964 FIG! United States Patent 3,358,841 CONTINUOUSLY-ACTING CEN'I'RIFUGE Iosif Naumovich Khibnik, Minsk, U.S.S.R., assigior to Minskoe Spetsialnoe Konstruktorskoe Bjuro tekstilnoi i legkoi promyshlennosti, Minsk, U.S.S.R.

Filed Oct. 15, 1964, Ser. No. 404,125 Claims. (Cl. 210-374) The present invention relates to continuously-acting centrifuges of the type comprising an Outer perforated drum and a coaxial inner drum, the latter being provided with a screw threading on its outer surface, both drums being mounted on a common shaft and rotated at different speeds.

Continuously-acting centrifuges now in common use are intended only for wringing out materials such as wool, which are kept in the centrifuge for a short period of time, so that the difference in speed between the outer perforated drum and the inner screw drum need not require control while the centrifuge is operating. Such speed difference remains constant during the entire running period, and is effected by the use of conventional reduction gears. With a screw drum having ten threads with 150 mm. pitch, conventional reduction gears allow the material to be kept in the centrifuge for a time not exceeding minutes. In order to prolong this time an increase in the number of threads may be employed, but this would result in a greater size and more complicated design of the centrifuge and in the maintenance thereof, and at the same time fail to enable the ratio between the speeds of the outer and inner drums to be controlled by the use of the reduction gear involved.

An object of the present invention is to eliminate the aforementioned disadvantages and to make it feasible to employ a centrifuge, a part from material wringing, also for difierent technological liquid-treatment processes, for example wool carbonization, fibre dyeing, washing of wool and other fibrous materials, which require the material to be kept in the centrifuge for a long time, with control of the relative speeds of the drums depending upon the character and duration of the working process. Another object of the invention is to provide such control without complicating the driving mechanism of the drums.

The above objects are achieved by providing the inner drum, in its lower portion, with a tooth rim meshing with a pinion fixedly mounted on an axle which is freely rotatable in a bearing fixed in the lower portion of the outer perforated drum. Additionally, on said axle there is rigidly mounted a ratchet wheel (of tooth or friction type) which is intermittently driven with the aid of a pawl arranged on a lever of a spring-loaded slide; this slide, in turn, is movable along guides fixed on the outer drum and is provided with a roller, interacting with an eccentric disc mounted on a movable carriage. As a result, with the rotational speed of the outer drum remaining invariable, shifting of the carriage with the disc, causes the pawl of the slide to rotate the ratchet wheel which in turn rotates the screw drum, the r.p.m. ratio of the drums being thus changeable allowing processing of the material in the centrifuge to be carried out for a time period of any duration in accordance with the requirements of the technological process for the material liquidtreatment and its wringing. The slide and the eccentric disc may be disposed in a vertical plane, thereby substantially reducing vibrations.

Other objects and advantages of the invention will be clearly understood from the following detailed description given with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic view of a continuously-acting centrifuge; and

3,358,841 Patented Dec. 19, 1967 FIG. 2 is the same taken on arrows A and B of FIG. 1.

Mounted on a frame 1 are two drums 2 and 3 arranged on a common shaft 4. Outer drum 2 having perforated walls is rigidly mounted on vertical shaft 4 and is driven by an electric motor 5. Inner drum 3 is provided with a screw threading 6 on its outer surface, and the lower portion of the drum 3 is encircled by a tooth rim 7, said rim meshing with a pinion 8' fixed on an axle 9 in a bearing 10, the latter being disposed in the lower portion of outer drum 2. Rigidly secured on the same axle 9 is a ratchet wheel 11 driven by a pawl 12 mounted on a lever 13 which is pivotally mounted on a spring-loaded slide 14 which is movable along guides 15 which are fixed on outer drum 2. The end of slide 14 supports a roller 16, which is forced by a spring 16' of said slide against a disc 17 fixed on a carriage 1-8 which slides along guides 19 fixed on frame 1. Carriage 18 is moved by means of screw 20 and nut 21, secured in frame 1. Material is charged through bunker 22 in the central part of inner drum 3. The axis of the charging orifice coincides with the axis of rotation of both drums, making it possible to continuously charge the material and effect discharge thereof to the screw thread 6 via two branch pipes 23 of said bunker and ports 24 on diametrically opposed sides of the inner drum. Consequently, there can be effected continuous operation of the centrifuge.

The centrifuge operates as follows.

With electric motor 5 activated, outer perforated drum 2 is driven in rotation along with hearing 10 mounted thereon, and axle 9 and pinion 8, whereby inner screw drum 3 is driven. Ratchet wheel 11 is moved along with axle 9 as well. Simultaneously with drum 2 slide 14 is moved, roller 16 of which rides over disc 17, set eccentrically in relation to vertical shaft 4 by means of said carriage 18. Thereby slide 14 is moved radially, imparting a rocking motion to lever 13 with pawl 12, the latter rotating ratchet wheel 11 along with axle 9 and pinion 8, thus changing the r.p.m. ratio between drums 2 and 3, due to which any relative speed may be obtained. For example, with a tooth rim diameter of 1000 mm., a pinion diameter of mm. and the number of teeth of the ratchet wheel equal to 240, the ratchet wheel for one revolution of outer drum 2, with pawl 12 adjusted for 1 tooth, turns through part of a revolution and for a period of 1 minute, with the number of revolutions of the drum being equal to 600, the number of revolutions of the ratchet wheel will be equal to 6O0=2.5 r.p.m. The same number of revolutions will be made by axle 9 and pinion 8; as a result, the tooth rim will make 2.5=0.25 r.p.m. Thus, for a period of 4 minutes the drums will be moved one revolution with respect to each other. In this case, with a screw drum having ten threads, the material will be kept in the centrifuge for 40 minutes. To control the relative speed, screw 20 is turned, and thus carriage 18 and disc 17, will move and will change the travel length of slide 14 and pawl 12. In case the eccentricity becomes zero during the adjustment, slide 14 and its roller 16 will not be moved radially, and the relative speed of inner screw drum 3 and outer drum 2 will become zero as well.

This being the case, the material being processed may remain stationary for any preset period in accordance with the treatment process. The treatment having been finished, disc 17 is engaged by turning screw 20, thereby imparting motion to the assembly of slide 14, lever 13, pawl 12, ratchet wheel 11 and, at the same time, imparting advanced motion to screw drum 3; the material being treated gradually moves up screw threading 6 and is discharged from the last thread thereof into a receptacle for the discharged material. Meanwhile the continuously charged material moves by gravity down bunker 22 and is supplied to the lower thread of screw 6 through ducts 23 and ports 24. Centrifugal forces thrust the material onto said screw threading and force it against the outer perforated drum thereby extracting liquid from the material during its gradual rise up said screw threading within a predetermined period of time.

Thus the continuously-acting centrifuge according to the invention with a controlled ratchet drive permits the material in the centrifuge to be kept stationary for any period required to perform the treatment processes and to wring the material, i.e. to accomplish any liquidtreatment process, thereby eliminating the necessity of carrying out separately the processing and the subsequent wringing of the material separately, thereby increasing the capacity and utilization efficiency of the processing equipment. The centrifuge design is simplified, since there is no reduction gear, which is the most expensive unit of the centrifuge, and requires careful maintenance while possessing a very low efiiciency due to the considerable frictional energy losses in tooth gearings as well as the great parasitic power losses produced in reduction gears.

What is claimed is:

1. A continuously-acting centrifuge for fibrous materials, comprising a frame, an outer drum with perforated walls, an inner drum concentrically mounted relative to the said outer drum, said inner drum including a screw thread on the outer surface thereof; means for rotatably mounting said drums on the frame; means for driving the outer drum in rotation; coupling means including first means on the outer surface of the inner drum and second means mounted on the outer drum, and engaging the first means for driving the inner drum in rotation as the outer drum rotates, means engaging said coupling means for supplying additional speed to the inner drum through said coupling means, means movably coupled to the last mentioned means for effecting continuous adjustment of the additional speed of the inner drum while the drums are in rotation, and means for charging material into the said centrifuge.

2. A centrifuge in accordance with claim 1, in which the means for driving the outer drum comprises a vertical shaft to which said outer drum is rigidly secured; an electric motor driving the vertical shaft; said second means comprising an axle mounted on the outer drum, and said first means comprising a toothed rack on the inner drum, a gear rigidly fixed on the said axle, interacting with the toothed rack of the inner drum; said means for supplying additional speed to the inner drum comprising a ratchet wheel rigidly secured on said axle and a pawl engaged with said ratchet wheel to prevent turning of such axle.

3, A centrifuge in accordance with claim 2, in which the means for supplying additional speed to the inner drum further comprises a spring loaded slide arranged in the lower part of the outer drum and interacting with the pawl to drive the ratchet wheel and thereby the inner drum, a roller on said slide, and an eccentric disc mounted on the frame and acting on the roller to impart radial movement to said slide.

4. A centrifuge in accordance with claim 3 in which the means for continuous adjustment of the additional speed of the inner drum comprises a displaceable carriage supporting said disc, a screw coupled to said carriage and a nut secured to the frame and interacting with the said screw such that rotation of the latter produces displacement of the carriage.

5. A centrifuge in accordance with claim 1 in which the means for charging the material comprises a bunker arranged on the vertical central axis of the drums and having in its lower portion two branch pipes forming a single horizontal duct, diametrically opposed ports leading to the bottom screw threads, said branch pipes being connected to the inner drum and having openings in communication with said ports.

References Cited UNITED STATES PATENTS 662,214 11/1900 Wood 210374 1,296,280 3/1919 Fussell 210374 1,589,097 6/1926 Behr 210-374 1,749,368 3/1930 Behr 210374 2,499,457 3/1950 Buquoi et al. 210-374 FOREIGN PATENTS 963,857 5/1957 Germany.

REUBEN FRIEDMAN, Primary Examiner.

I. L. DE CESARE, Assistant Examiner. 

1. A CONTINUOUSLY-ACTING CENTRIFUGE FOR FIBROUS MATERIALS, COMPRISING A FRAME, AN OUTER DRUM WITH PERFORATED WALLS, AN INNER DRUM CONCENTRICALLY MOUNTED RELATIVE TO THE SAID OUTER DRUM, SAID INNER DRUM INCLUDING A SCREW THREAD ON THE OUTER SURFACE THEREOF; MEANS FOR ROTATABLY MOUNTING SAID DRUMS ON THE FRAME; MEANS FOR DRIVING THE OUTER DRUM IN ROTATION; COUPLING MEANS INCLUDING FIRST MEANS ON THE OUTER SURFACE OF THE INNER DRUM AND SECOND MEANS MOUNTED ON THE OUTER DRUM AND ENGAGING THE FIRST MEANS FOR DRIVING THE INNER DRUM IN ROTATION AS THE OUTER DRUM ROTATES, MEANS ENGAGING SAID COUPLING MEANS FOR SUPPLYING ADDITIONAL SPEED TO THE INNER DRUM THROUGH SAID COUPLING MEANS, MEANS MOVABLY COUPLED TO THE LAST MENTIONED MEANS FOR EFFECTING CONTINUOUS ADJUSTMENT OF THE ADDITIONAL SPEED OF THE INNER DRUM WHILE THE DRUMS ARE IN ROTATION, AND MEANS FOR CHARGING MATERIAL INTO THE SAID CENTRIFUGE. 